The invention is applicable for producing coatings in vacuum to an object, for example diamond-like carbon coatings, to extend life of cutting, shaping and measuring tools, friction units and parts of machines, as well as to improve biological compatibility of implants in medicine, and to extend life of video and audio read/write heads in electronics.
A vacuum coating apparatus for coating materials with a diamond-like coating using a pulsed plasma beam comprising electrodes coupled to a voltage source, a storage and a deflecting coil is known from U.S. Pat. No. 5,078,848. The apparatus described in U.S. Pat. No. 5,078,848, however, has an insufficiently reliable arc striking device and does not permit depositing coatings on extended objects. Furthermore, the coating produced is highly nonuniform in thickness.
The closest prior art is a pulsed carbon plasma apparatus comprising a consumable graphite cathode and an anode, both accommodated in a housing of a vacuum chamber and having a common geometrical axis, the consumable graphite cathode and the anode being electrically coupled to a capacitive storage shunted to a dc charger, and an arc striking device disposed in the vacuum chamber and connected to an initiation unit (see e.g. A. I. Maslov et al., Journal of Experimental Instruments and Methods, No. 3, 1985, pages 146-149). This apparatus has a restricted region of depositing a coating, and the coating produced is highly nonuniform. Focusing the plasma flow by the use of a focusing solenoid improves efficiency in the center, but still further increases the thickness nonuniformity of the coating. This method for controlling the energy characteristics suffers a number of deficiencies. With variation in the voltage of the capacitor, the charge of the capacitor is modified, resulting in variation in the cathode erosion region and, consequently, in the coating deposition area, leading to inhomogeneities. Furthermore, with a reduction in the capacitor voltage below a certain value, the reliability of initiating a discharge pulse is reduced. An increase in the capacitor voltage above a predetermined threshold leads to uncontrolled electrical breakdowns between electrodes, resulting in contamination of the carbon plasma and deterioration of the properties of the diamond-like condensate that is formed on the object.